US2686911A - Clincher mechanism for nailing machines - Google Patents

Description

Aug. 24, 1954 J. R. RICHARDS Filed March 28, 1952 7 Sheets-Sheet 2 2o 4o. "IlE-' 2A BI do 0 0 0 665 as 87 "INVENTOR JOHN R. RICHARDS ATTORNEY g- 24, J. R. RICHARDS 2,686,911

CLINCHER MECHANISM FOR NAILING MACHINES Filed March 28, 1952 7 Sheets-Sheet 3 INVENTOR JOHN R. mcnARos B M/W'Awk ATTORNEY Aug. 24, 1954 J. R. RICHARDS 3 55 CLINCHER MECHANISM FOR NAILING MACHINES Filed March 28, 1952 Sheets-Sheet 4 INVENTOR JOHN R. RICHARDS BY A m,

ATTORNEY g- 24, 1954 J. R. RICHARDS 2,686,911

CLINCHER MECHANISM FOR NAILING MACHINES Filed larch 28. 1952 7 Sheets-Sheet 5 WA fl 'F'Il3 Ei Q w m v I I m V 0 C J m H m P w F 8 INVENTOR JOHN R- RICHARDS .8 mkugjw ATTORNEY J. R. RICHARDS CLINCHER MECHANISM FOR MAILING MACHINES Filed llarch 2 8, 1952 Aug. 24, 1954 7 Sheets-Sheet -6 s 2;, m n W n O 2.; A. mm. a a J w w m I V m T w 2... a T M on: V am no. u m9 nn SM n 5: 2... 4.7 mfi. m: 3 1 QQ- 2 m wn. a O 0Q m 0 no. cow mm... Q A mom on. on. Nb. 7 mmw m. mm v w. w 2 m. o l P n. N-.. b M a N.m mm. 2.. m v m\ :2 02 w 0 an .0: x\ v 0 .mm mm: a. 9. 3? mm s. om. My 5; am. o: f on. m ww Om; m! mm Aug. 24, 1954 J. R. RICHARDS CLINCHER MECHANISM da NAILING MACHINES 7 Sli'eets-Sheet 7 INVENTOR: Jrm n. mcnnnus Filed March 28, 1952 ATTORNEY Patented Aug. 24, 1954 CLINCHER MECHANISM FOR NAILIN G MACHINES John R. Richards, Riverside, Calif., assignor to Food Machinery San Jose, Calif.,

and Chemical Corporation, a corporation of Delaware Application March 28, 1952, Serial No. 279,013

24 Claims.

The present invention relates to machines adapted to nail flatly superposed slats, boards or planks together. Machines of this type are commonly employed to produce the side walls, or lids of cases, crates and the like. When nails are driven through flatly superposed slats, such as is the case when several juxtaposed slats are joined into the lid or side Wall of a case by nailing a common board across them, the points of the nails may protrude from the underside of the slats, which renders the cases dangerous to handle and impairs their useability. For this reason it is necessary to clinch the projecting nail points which has the added advantage of increasing the sturdiness of the structure joined by the nails.

It is an object of the present invention to provide a nailing machine of the type referred to, that is operable to clinch the points of nails driven through thework.

Another object is to provide a nail point clincher for nailing machines, of the type referred to, that is simple in constructionyet eifective, fast and dependable in operation.

Still another object is to provide a clincher mechanism, of the type referred to, that may readily be installed in,- and operatively connected to the power train of, nailing machines of conventional design.

An additional object is to provide nailing machines of the type referred to with a clincher mechanism that is effective to clinch the point of nails driven through boards or planks without extending the period of time required by the nailing machine for each nailing stroke.

Yet another object is to provide a nailing machine with a clincher mechanism that operates simultaneously with the nailing operation, such that the clinching operation is completed by the time the nail or nails have bten driven fully through the slats or boards to be joined.

A further object is to provide a simple and effective actuating arrangement for nail point clincher mechanisms of the type referred to.

Moreover, it is an object to provide, in nailing machines of the type referred to, a clincher actuatin mechanism that is eifective to drive the clincher from the same source of power as, and in timed relation with, the actual nailin mechanism of the machine. These and other objects of the present invention will be apparent from the accompanying drawings which illustrate a preferred embodiment thereof and wherein:

Fig. 1 is a side elevation of a mailing machine embodying the clinchermechanism of the invention.

Figs. 2A and 2B are the left and right half, respectively, of a front elevation of the machine illustrated in Fig. 1 with certain parts broken away to expose details of the clincher mechanism.

Fig. 3 is a fragmentary vertical section through the nailing machine taken alon line 33 of viewed from a point in front, and to the right,

of the machine as shown in Fig. 23.

Fig. 8 is a fragmentary perspective of the actuating mechanism for the clincher mechanism illustrated in Fig. '7, viewed from a point to the right and rearwardly of the machine as shown in Fig. 2B; and

- Fig. 9 is a fragmentary plan view of said actuating mechanism.

Having first reference to Figs. 1, 2A and 2B, the exemplary nailing machine to which theclincher mechanism of the invention is applied comprises briefly a nail supply pan or hopper 23 that is v (Fig. 3) may pivotally connect the front or discharge end of the hopper 20 to an arm 2T that is firmly mounted upon a transverse shaft 28 which is suitably journaled in the above mentioned side panelsZZ and 23. Firmly secured to said shaft 28 is a rearwardly extending arm 29 (Fig. 1) that is continually rocked in clockwise direction by a pitman so which has a slotted upper end 3! that is engaged over a stud 32 which projects laterally from said arm 29. The lower end of the. pitman 30 is pivoted to a crank disc 33 that is mounted upon a transverse shaft 34 which is suitably journaled in the side frame 36 of the machine. Durin operation of the machine a suitable source of rotary power, such as the electric motor 3?, maintains said shaft 3% in a continuous state of rotation through a suitable train of gears and sprockets collectively identified by the reference numeral 39. In Fig. 1 the pitman St is shown in its elevated'position in which it permits the hopper 20 to dro under its own weight and under the weight of the nails contained therein into the rearwardly declined position illustrated in said figure, from whichit i raised into its forwardly tilted position (Fig. 3) as rotation of the crank disc 33 pulls the pitman its into its lowermost position. When the hopper 29 is in said last mentioned position, the nails contained therein gravitate toward the discharge end thereof. Formed :in-thefloor of the hopper 28 near the discharge end thereof are many longitudinal channels (not visible) through which the stems of the nails may drop, but which are of such limited transversewidth as to retain the heads of the nails above the hopper floor. Hence, when the hopper 20 is .in'the forwardly tilted position shown in *Fig. 3, nails will drop with their stems throughsaid channels but their heads will be retained in the hopper, and the nails will therefore gravitate. along said channels toward the discharge end of the hopper. Arranged across the discharge end of the hopper 2B is a weir in the form of a transverse bar 46 (Figs. 2A and 2B) the lower edge of which is provided with recesses (not visible) one above each of the described channels, that areof such limited depth that only the heads of nails'hanging through said channels may pass underneath the weir, while the bulk or the nails inthe hopper is retained therein. Beyond the weir 40, transversely spaced, downwardly inclined angle bars :33 that are rigidly supported from theside panels 22 and 23 in a suitable manner, form continuations at of the aforementioned nail guiding channels in the floor of the hopper 20. Within and along said channel continuations' lt thet'nails passed by the weir it gravitate in orderly single'file lines toward the lower ends thereof, where gate mechanisms 45, commonly known as nail picks,'are provided that normally block the flow of nails from said channels lt but open briefly during each operating stroke of the nailing machine to permit a single nail to dropfrom each channel l4 into a funnel .tt disposed underneath to replace the nails used up in" said operating stroke. Having referencerto Figs- 3. and 4, each of said nail picks t may; comprise a'rotor segment is that is pivoted to a crossbar 49 supported from the hereinbefore mentioned side. panelsi22 and '23 and which presents a beveled arcuate edge 56 to the end of its respective nail guidingxchannel M, suitable spring means. 5i being. provided to: 'yieldably hold said segment 5-8 in arotaryi position ."wherein a recess 52 provided'in its fbeveled' iedgefit and-adapted to receive a' single nail isaligned withv its respective channel lisuchethat ther'foremostoneiof the nails gravitating u'down -;:saidv channels will "leave saidchannel-and come to:rest iwithinsaid-"recess.

Whenever .the nailin machinez p'erforms a nailingstroke thatxusesup arset rif nai'ls;:=,means, enter into operationztha't turn the rotorli segments 5 8 temporarily abouttheinpivotpoints 318a such that the single znailsfheld inthe' recesses 52 may slide 1 down the beveled? upper surface: thereof: and drop from the'rotor segments .afl intoithe funnelsilifi below,r-While that-portions of; said irotors'segments adj oining" said: recesses".ziblocki thev respective Inail supplying zchannels 44,-ezwhereupon" the rotorrsegments 48 return to their initial position under the -machine said rollers 55 engage temporarily a suitable camming surface 55 provided on their respective rotor segments ts to turn said rotor segments in the manner described above against the urgencyof their restore springs it. To turn the shaft .5 3 over an arc efiective to release a single nail through each gate mechanism 55, whenever the machine performs a nailing stroke, said shaft 5 3. may carry on one of its ends a ratchet 5'5 (Figs. 1, 2B and 3) which is engaged by an actuating pawl 58. Said actuating pawl as is pivoted to a link 68 that in turn is pivoted to one end of a bell crank 6E whichis pivotally supported from the side panel as shown at 62 in Figs. 1 and'3.

The other end'of said bell'crank iii ispivotally connected toa link E3 which in turn is pivotally connected to a lug projectin rearwardly from a rectangular frame 55, that is arranged to slide vertically upon and along the side frames 35 and 36 of the machine. The rectangular frame 65 actuates the means that drives the nails through theboards to be joined as will be presentlydescribed in greater detail. Thus, whenever the rectangular slide fii'l is lowered to drive a setof nails into the work tobe joined, the pawl 58is actuated to turn the cam shaft E l over an are that will release a single nail from every one of the'gate mechanisms 45.

The nail receiving funnels '45 disposed below the gate mechanisms 55 are stationary being rigidly supported in a suitable manner from the top of the machine frame, and they guide the nails received from the gate mechanisms through flexible tubular conduits K into nail chucks 69 that bring the nails into proper position above thework for the actual nail driving or punching operation. For this purpose, said nail chucks may be arranged to descend from a level a predetermined distance above a work supporting table or anvil it arrangedin front of the machine into contact with the work that may lie on said'anvil. To permit the flexible conduits 3% to move with the nail chucks 69 with-- out impairment of their task of guiding thenails from the nail picks swiftly and without obstruction to said nail chucks, the upper ends of said conduits may be provided with additional funnels N that are suitably supported from and move with the hereinbefore described slide 55 and which telescope over the elongated tubular extensions !2 of the previously described stationary nail receiving funnels 45. 'The nail chucks 69 may be formed by blocks 13 having vertical channels 14 adapted to slidably receive the rods 15 that actually drive the nails into the work and which are commonly known as nail punches. In the exemplary embodiment of the machine illustrated in the accompanying drawings each nail fchuch-tfillwith its channel'ld is formed by two blockisectionsna and 1317' (Fig. 3A) that are held together by a strong spring brace is which mayrpe'rmit'saidfblock sections to slide apart, should the punch 15 encounter an obstruction 'withinthechanne'l" M such as maybe formed by an inappropriately positioned-nail. The hereinbefore adescribed 'nail supplying conduits 66 are each connected to an inclined lateral passage I1 provided in the block section l3bso that nails in the chuck. Said jaw 18 may be formed by a pair of leaf springs 18a and 18b that are supported within the slottedlower end of each block. 13 in the manner of a V converging below the bottom end of the channel 14. All nail chucks 69 provided in the machine are adjustably supported from a crossbar 80. .At its opposite ends said crossbar is supported from brackets 8| (Figs 2A and 2B) which slide within guide grooves formed by vertically spaced horizontal guide bars 82 (Fig l), but are secured in adjusted position relatively to said guide bars during operation of the machine. Said guide bars in turn are part of a carriage 83 (Figs. 5 and 6) that slidably engages the side frames 35 and 36 of the machine v below the hereinbefore described rectangular slide 65 and which is operatively coupled for limited reciprocatory vertical movement with the hereinbefore mentioned slide 65 in a manner to be presently described.

Supported from. and below the rectangular frame of the slide 65 for adjustment longitudinally of the machine is a plurality of horizontally positioned parallel beams 85 that extend longitudinally of the machine, andsuitably supported from the front end of said beams is a transversely extending bridge member 86. On its underside said bridge member 86 carries a plurality of transversely spaced parallel racks 81 from which are suspended the hereinbefore mentioned rod shaped nail punches 15, one for each of the nail chucks 69 provided in the machine. The uppcr ends of said rod shaped punches I5 are radially extended in the manner of a T to form fiat upper surfaces that face the underside of the bridge member 86 and which are positively engaged by said bridge member during descent of the rectangular frame 05 as soon asthe lower ends of the punches encounter resistance such as is the case when they engage the heads of nails. within the chucks. To actuate the slide BS pitma-ns 90 (Fig. 1) pivotally connect said slide through suitableshock absorbers 9i to aligned eccentric points 92 of crank wheels 93 that are mounted upon the opposite ends of a transverse shaft 94 suitably journaled in the side frames 35, 36 of the machine near the pedestal 95 thereof. Said shaft 94 may be driven from the aforementioned electric motor 3'! through a suitable power train, collectively identified as 96 in Fig. 2B which includes a single revolution clutch 91 that may beengagedby depressicn of a suitable pedal switch 98 disposed in front of the machine (Fig. 1). As pointed out hereinbefore, the electric motor is in a continuous state of rotation during operation of the machine and by depression of the pedal switch 98 the power of said motor is applied to the crank wheels 93 for the time of a single revolution thereof.

When the nailing machine is in its position of rest, both, the nailing punches l5 and the nail chucks 69, are raised sufficiently high above the table or anvil 10 to permit the work to be placed thereon, with the punches sufliciently withdrawn from their respective chucks to provide space in the channels 14 for a nail to rest itself with its point upon the converging end of the spring jaws 18 of the chucks. During the nailing operation, however, the nail punches I5 must be arranged to descend at a faster rate than the nail chucks and to a level somewhat lower than the lowermost level reached by said chucks in order that they may drive the nails from the chucks into the work once the chucks have come to a halt above the work. Referring again to Fig. 1, said figure illustrates the initial or full cycle position of the actuating mechanism for the rectangular slide 55, wherein the crank wheels 93 hold the pitmans 90 and hence the slide 65 and the nail punches I5 at their highest position. When the nail punch supporting slide is in the defined elevated position, it is arranged to positively hold the nail chuck supporting carriage 83 in a sufiiciently elevated position to raise the chucks above the anvil I0. For this purpose, the opposite sides of the carriage 83 may be provided with ledges I00 (Fig. 5) that rest upon studs it! which project from links I02 that are pivotally secured to the sides of the slide 55 at points which lie above the level of the ledges I00 when said slide is in its extreme elevated position. Upon depression of the pedal switch 98 the crank wheels 03 commence to turn in clockwise direction as viewed in Fig. 1 causing the pitmans 90 to lower the slide 65. As said slide descends to lower levels, it also lowers the studs IOI and thus permits the carriage 83 supported on said studs to drop to lower levels under the force of its own weight.

The carriage-supporting studs I0l, however, are

also pivotally supported from the adjacent stationary side frames 35 and 36, respectively, at points I03 by means of second links I04 of predetermined length. As a result of the described connection the carriage supporting studs I H in stead of dropping along a vertical line, will describe an arc and slide along the bottom edges l00a of their respective ledges I530 limiting the descent of the carriage 83- to a drop equal to the distance between the stationary pivot points I63 and the center axis of the studs Ii]! (Fig. 6). In the exemplary mechanism illustrated in Figs. 5 and 6, the drop of the carriage 83 is somewhat increased beyond the defined distance by arouately beveling the front edges I03?) of the ledges I00 such that said ledges may actually drop a limited distance below the summit of their supporting studs IOI.

By interposing a lost motion linkage of the type here described between the slide 65 and the carriage 83, the former controls the descent and also the return movement of the latter such that with every revolution of the crank wheels 0?; the slide 65 will descend at a faster rate and over a greater distance, and vice versa, will rise at a faster rate and over a greater distance than the carriage 83. In this manner the nail punches will be suiiiciently Withdrawn from their chucks at the beginning of each operational cycle of the ma chine to unblock the nail feeding passages 17 and leave space for nails in the chuck channels Hi, but will upon commencement of each nailing operation progressively enter the simultaneously descending nail chuck, and eventually engage the heads of the nails within the chucks as said chucks come to rest upon the work. The punches will then push the nails through the yielding jaws I8 into the work on the anvil I0 underneath.

. after continuedrotation of said crank wheels will raise the punches 15 within the chucks 6.9, and

then'raise both the punches'and thechucks'until both reach their initial full cycle position, with the former almost withdrawn from the latter as illustrated in Figs. 1 and 3.

fore, oscillates the hopper Zil continually between the reclined position shown in Fig. 1 to the forwardly tilted position shown in Fig. 3. Whenever the hopper 20 is in the latter position nails will fill the guide channels provided in the forward portion of its bottom and will gravitate in orderly single flle underneath the weir bar it onto the declined channel continuations M, with the foremost nail in each file coming to rest with in the recess 52 of the nail pick mechanism d provided at the lower end of each channel.

To illustrate a preferred form of cooperation between the nail pick mechanism and the actual nailing mechanism of the described machine, let it be assumed that the nail picks have already passed a nail each and delivered it through the flexible conduits 66 into a respective chuck 59, where it enters the center channel thereof since the nail punches-are in their upwardly withdrawn full cycle position illustrated in Fig. 3 in which the side passages H are unblocked. Each of the nail chucks 69, therefore, contains a nail that rests with its'point upon the yieldable jaw l8.

To set the actual nailing mechanisms into op eration, the operator steps on the pedal switch 98 which connects the crank wheels 53 for a single revolution to the power train of the continuously operating motor 31. As the crank wheels commence to turn in clockwise direction as viewed in Fig. 1, they pull the rectangular slide 65 downwardly which lowers the punches 15 supported therefrom upon the work piece on anvil Hi. Descent of the slide 65 releases the carriage 83 which drops under its own weight and the weight of the assembly carried therefrom at a rate controlled by the hereinbefore described lost motion linkage [GE/lat until the nail chucks supported from said carriage come to rest upon the work piece on the anvil. The descent of the slide 55, however, continues under the pull of the pitmans es, and the punches l5 therefore push deeper into the chucks, engage the heads of the nails contained therein and push the nails through and past the yielding spring jaws out of the chucks and fully into the work to be joined.

As the rectangular slide 55 is pulled downwards in the described manner, it pulls the link 53 that is pivotally connected to the lug 64 on its rear wall as described hereinbefore. As a result thereof, the bell crank (ii is rocked in'clockwise direction as viewed in Figs. 1 and 3 which actuates the pawl 58 to rotate the shaft 5t that carries sets of nail pick actuating rollers 55 for each of the nail guiding channels Ml as explained hereinbefore. The described actuation of pawl 58 turns said shaft 54 over an are that brings one of said rollers 55 in each set briefly into engagement with the camming surface 56 of each rotor segment 48 causing the rotor segments to swing briefly sidewise and deposit the solitary nails in their recesses 52 into the funnels it underneath which deliver them through the flexible conduits 66 into the side passages 11 of the various nail chucks 59. At this moment, however, the punches are fully inserted into the chuck channels "so that the nails are blocked from entrance into-said channels and remain in the side passages 1-1 of the chucks. After completion of the nailing stroke, however, during the second and final half of the single revolution of the crank wheels 93, the slide 65 is raised to its initial position which withdraws the punches [5 from the work. The return movement of the slide 65 isalso effective to raise the carriage 83 from which the chucks 69 are supported. However, the return movement of said carriage 83 occurs at a slower rate andiis limited to a shorter distance than the return movement of the slide 55 due to the described lost motion linkage lilZ/llltthat couples the carriage to the slide. As a result thereof the punches l5 withdraw from the chucks E9 to the extent illustrated in Fig. 3 unblocking the side passages 1'! thereof, so that the single nails retained in said side passages by the punches in their state of depression may now slide into the channels 14 and rest themselves with their points against the closed bite of the resilient jaws 18. Thus, by the time the crank wheels 93 have completed their revolution and slide 65 and carriage 83 have returned to their full cycle positions in which they hold the punches l5 and the chucks 69, respectively, a sufficient distance above the anvil 10 to permit handling of the work piece, the chucks 69 are already charged with a new set of nails so that the machine is immediately ready for an other operational cycle.

The mechanism for clinching the points of nails driven through the work piece in the described nailing operation is located in the repeatedly mentioned anvil Ill in that the work supporting surface I55 of said anvil is arranged to contain a vertically retracted area, adjacent its inner transverse edge directly below the nail punches 15, which is normally situated at a somewhat lower level than the remaining anvil surface but is operable to rise temporarily to said level toward the end of each nailing stroke of the nail punches. Having reference to Figs. 1, 2A and 2B the anvil structure illustrated therein comprises a pair of transversely spaced consoles um and 19 which are connected at their inner ends by an edgewise positioned transverse plank Hi] and which carry the anvil table lll. At the rear side of the plank HE! the consoles I08 and its form slide brackets H2 and H3 (Figs. 8 and 9) which embrace guide posts H4 and H5, respectively, that are suitably secured to the side frames 55 and 36 of the machine along the vertical front edges thereof. Said brackets H2 and l is carry internally threaded loops I 12a and 3a that are engaged by correspondingly threaded vertical rods H6 and Ill which rise vertically from the machine pedestal 95 (Figs. 2A and 2B) and are rotatably supported from the machine frame. By turning the vertical rods I I6 and I ll the vertical position of the anvil consoles and hence of the anvil table may be varied and to this end a hand crank H9 arranged at the outside of the right hand side frame 35 (Fig. 1) may be operatively connected to the right hand rod ill by a suitable power train which is collectively identified by the reference numeral I20 and which will usually include a Worm gear transmission (not visible). At their lower ends the threaded rods H6 and Ill may be operatively connected for rotation in unison by a suitable sprocket train as indicated by the sprocket chain I 2I that is visible in Figs. 2A and 2B. Thus, by turning the hand crank I I9, the threaded rods I I 6 and I I1 may both be rotated in unison, which is effective to raise or lowerthe total anvil depending upon the direction of operation of said rods.

Having specific reference to Figs. 3 and 9, in the anvil of the present invention the table plate I I I does not extend all the way to the transverse plank II at the rear end of the consoles I00 and I09 but terminates adjacent another edgewise positioned vertical plank I22 whose upper edge is flush with the work supporting surface of the table plate and which is supported from the consoles I06 and I09 in a position parallel to, and a short distance in front of, the first mentioned transverse plank H0. To securely maintain the planks I I 0 and I22 in their properly spaced relation, spacer blocks I21 may suitably be interposed between their ends and additional spacer blocks I29 may be interposed between intermediate pointsthereof. In addition, a number of spacer fillets I30 may be countersunk into the upper edges of the planks at equal intervals transversely of the anvil structure as best shown in Fig. '1. Bolted to the lower edges of the planks H0, I22 at intervals transversely of the machine are boards I33 that serve as supports for rollers I34 whose axes extend longitudinally of the machine and which turn on spindles I35. The ends of said spindles protruding from the opposite faces of said rollers I34 are heldin the lower ends of parallel links I36 whose upper ends are connected by a hinge stud I31 that turns in a respective one of a plurality of apertured bosses I38 provided on the underside of a number of transversely juxtaposed base members I40 which lie between the planks H0 and I22. In a direc tion transversely of the anvil structure each of said base members fills one of the spaces between the spacer blocks I21 and I29, respectively, and to this end said base members I40 loop downwardly below each of the described spacer fillets I30 as best shown at MI in Figs. 23 and to provide guide grooves I42 within which the lower edges of said fillets are slidably received. Suitably 1 secured to the intermediate portions I43 of said base members I40 such as by means of screw studs I43a projecting upwardly from said portions I43 are two vertically superposed horizontal plates I44 and I45 of rectangular conformation to fill the rectangular spaces defined by the planks IIO, I22 and the fillets I30 or spacer blocks I21 and I29, respectively. The lower ones I of said rectangular plates may be made from a relatively soft material, such as soft iron, but the upper ones I45 are preferably made of hardened steel, since they form the table area that is retracted below the actual work supporting surface I of the anvil as determined by its table plate II I and the upper edges of the consoles I08, I09, the planks IIO, I22, the spacer blocks I21, I29 and the fillets I 30 when the machine is at rest. As previously pointed out said retracted area is temporarily elevated to a level flush with said surface, coincident with the final phase of each downward stroke of the nailing punches 15.

To effect this elevation of the rectangular plates I45 the projecting ends of the roller spindles I35 are engaged by and project through a pair of elongated draw bars I41 and I48 arranged at either side of the rollers I34 adjacent the end faces thereof. These draw bars extend from a point adjacent the left spacer block I21 transversely across the total length of the anvil structure with their right ends projecting laterally below the right spacer block I21 and beyond the right console I09. A number of strong springs I52 tensioned between studs I53 mounted in the draw bars and stationary points, such as eyes I54 secured to the roller supporting boards I33, normally urge said draw bars to the left as viewed in Figs. 2A, 2B and '1.

Since the base members I40 are unable to move in a direction transversely of the machine, due to the presence of the described spacer blocks and spacer fillets, any movement of the drawbars I41, I46 upon the rollers I34 under the force of the springs I52 causes the roller links I36 to assume a tilted position wherein they decline in leftward direction, as viewed in Fig. '1, and when so declined support the base members I40 in a position wherein the table plates I45 lie below the level of the remaining work supporting anvil surface I05. Means are provided, however, to pull the bars briefly to the right, and whenever this occurs the rollers I34 move to the right on their supporting boards I33, but with the base members I40 supported from said rollers unable to follow suit, due to the presence of the spacer blocks and spacer fillets, the links I33 assume a vertical position and raise the base members I40 to such an extent that the upper surfaces of the rectangular plates I45 are flush with the upper edges of the planks IIO, I22, the spacer blocks I21, I 29, the spacer fillets I30 and the anvil table III.

To effect the described movement of the drawbars I41, I48 in proper synchronism with each downward stroke of the nail punches 15, a snail cam I60 (Fig. 1) may be secured to the right one of the hereinbefore described crank wheels 93 which actuate the nail punch carrying slide 65. The edge of said snail cam I60 is engaged by a roller I6I that is pivoted to one end of a bell crank I62 which may have the form of a triangular plate whose apex is rotatably supported from the right side frame 36 of the machine as indicated at I63. The other end of said bell crank I62 carries a camming roller I 64 that is arranged to bear against the outer surface of the connecting bar I65 of a U-shaped bracket I66 (Fig. 7)

whose parallel shanks I61 and I68 are slidably received within guideways I69 and I10 (Figs. 7 and 8) of corresponding size that are formed in a stationary casting I1I which is bolted to and projects laterally from the vertically positioned outer surface I12a of a mounting plate I12 that is bolted to the right console I09 and which has a suitable aperture I12b through which the right ends of the draw bars I41, I40 protrude. Said casting I1I forms a rearwardly directed vertical surface Illa adjacent to and in front of the laterally directed aperture 1121; in the mounting plate I12. Rotatably secured to the shanks I61, I68 of the U-shaped bracket I66 by pivots I13 at points near the connecting bar I05 thereof, are the ends of a pair of parallel arms I14, Il'5, the opposite ends of which engage a vertical shaft I16 that is supported in a block I'llheld between and bolted to the protruding ends of the drawbars I41, I48. The upwardly and downwardly projecting ends of the vertical shaft I16, carry rollers I 18 and I19, respectively, that bear against the hereinbefore described rearwardly directed vertical surface I1Ia of the casting I H and rollers I and I8I may be secured to the projecting ends of the pivots I13 by which the arms I 14, I15 are secured to the shanks I61, I68 of the U-shaped bracket I66, to bearagainst the outer surface I120; of the mounting plate I12 and thus facilitate movement of said bracket along said plate.

When the machine is at rest with the bell crank I62 in the idle position illustrated in Fig. l, in which its cam follower roller I! engages a sector I55a of the snail cam I65 removed from the center point thereof by a minimum radius, the camming roller I64 is in its extreme clockwise position and the U-shaped bracket IE6 is therefore free to withdraw from the casting IN to an extent permitting the springs I52 to pull the drawbars I41, I48 into the extreme left position illustrated in Fig. '1, in which the rectangular table segments I45 are dropped below the work supporting surface I05 of the anvil. Under these conditions, the shaft I16 held between the outwardly protruding ends of the drawbars I51, I48 is drawn closest to the outer surface I12a of the mounting plate I12. However, whenever a nailing cycle is initiated by depression of the pedal switch 95 and the crank wheel 93 turns in clockwise direction as viewed in Fig. 1 and pulls the nail punches 15 downwardly to drive the nails from the chucks 59 into a work piece on the anvil 15 in the manner described hereinbefore, the cam follower roller I6I encounters cam points I551; of increasing radii, which is effective to swing the bell crank I62 in counterclockwise direction and bring its camming roller I64 against the connecting bar I65 of the U-shaped bracket I55 forcing said bracket to slide with its shanks I51, I58 deeper into the casting I1I. However, the twin arms I14, I15 pivoted to said shanks bear with their rollers I15, I19 against the immovable outer surface I1Ia of the casting Ill and are therefore forced to swing in counterclockwise direction, with said rollers I15, I15 traveling along said surface I1Ia, in a direction at right angles to and away from the surface IIZa of the mounting plate I12. drawbars I41 and I45 and pulled outwardly against the force of the springs I52, and as they move to the right as viewed in Fig. '1, the twin links I35 are straightened from the tilted position illustrated in said Fig. '7 to an upright position which raises the table plates I45 to the level of the remaining anvil surface I55. This occurs as the crank wheel 95 to which the cam I55 is secured operates to lower the nail punches. Hence, as the table segments I45 are rai ed in the described manner, they engage any nail points that may appear on the underside of the work piece as the nail punches drive the nails positively through the work piece, and as a result thereof, the nail points are bent sidewa'rds and finally backwards into the underside of the work piece. As soon as the effective stroke of the nail punches 15 has reached its maximum amplitude, however, corresponding to the lowest position to which the crank wheel 53 may pull the hereinbefore described nail punch carrying slide 55, the cam follower roller I5I on bell crank I52 drops from the maximum elevation I650 of the snail cam contour over a steep decline IBIIcZ onto the sector of minimum radius Ifiila, and as a result thereof, the bell crank I52 releases the U-shaped slide bracket I65. This permits the restore springs I52 to return the drawbars I41, I45 to their initial position and lower the table segments I45 below the remaining work supporting surface I55 of the anvil 15. Hence, by the time the nail driving mechanism has returned to its full cycle position, the clinching mechanism has likewise reached its initial position in which it is ready for another operational cycle of the nailing machine.

As a result thereof, the

ill

Means may be provided to adjust the effective amplitude of the clinching stroke. For this purpose, the camming roller I54 which engages the U-shaped slide bracket I55 may be pivoted to a bar I95 that is journaled on the pivot I53 of the bell crank I52 and is adjustably secured to said bell crank by means of screw bolts IIJI which protrude through slotted apertures I52 in said bar, and. a set screw I93 threadably received in an apertured ear I95 projecting laterally from the bell crank plate I52 may be arranged to engage a block I55 that is countersunk in the adjacent edge of the bar I55. Thus, when it is desired to increase the lift imparted to the table segments I by operation of the cam follower lever I52, the bolts IBI are loosened and the set screw I93 is turned to push the bar a limited distance in counterclockwise direction as viewed in Fig. l whereupon the bolts I5I are tightened again to firmly hold the bar I in its newly adjusted position. Vice versa, if it is desired to decrease the lift imparted to the retracted table segments I45, the bolts ISI are loosened and the set screw I93 is turned to withdraw from the bar I95, whereupon said bar is shifted in clockwise direction as viewed in Fig. l and the set screws are tightened again.

Means may also be provided to disable the described clinching mechanism in a position in which the table segments I55 are fully raised to the level of the remaining surface I55 of the anvil 15, such that said anvil presents an uninterrupted sclid supporting surface to the work. For this purpose a rod I suitably anchored in the connecting link I55 of the u shaped bracket I66 at the inner surface thereof may be arranged to extend through elongated slots I39 and .255 in the drawbars I41, I45, respectively, (Fig. 7) and suitable apertures 25I in the casting ill to project from the front surface of said casting. Its forwardly projecting end may be threaded as shown at 252 to receive the internally threaded tubular hub 253 of a hand wheel 254 (Figs. 1 and 9 Thus, by turning said hand wheel in one direction the rod I58 may be pulled forwardly forcing the U-shaped slide bracket I55 with its shanks I51 and IE5 into the casting I1I to a depth effective to hold the drawbars I41, I45 permanently in a position in which the table segments I45 are fully elevated and the slide bracket I55 itself is permanently out of reach of the camming roller I54 on the bell crank I52. On the other hand, a restore spring 255 coiled around the rear end of the rod I98 and interposed between the surface I1 is of the casting III and the connecting link I55 of the bracket I55 is effective to advance said bracket within reach of the camming roller its, whenever the hand wheel 254 is turned in the opposite direction, so that the table segments may drop below the level of the work. supporting anvil surface I55 and the bracket I66 again be acted upon by the camming roller I64.

While I have explained my invention with the aid of an examplary embodiment thereof, it will be understood that I do not wish to be limited to the specific constructional details shown and described which may be departed from without departing from the scope and spirit of my invention.

I claim:

1. In a nailing machine having a descending nail punch, a nail point clinching anvil structure comprising a frame presenting a work supporting table surface, a supporting plate secured to said frame below the level of said work supporting table surface, a roller supported by said plate and constrained to move thereon along a rectilinear path in a direction parallel to said table surface, a member adapted to form a segment of said table surface below and in vertical alignment with the nail punch, a link pivotally supportingsaid member from said roller, means blocking movement of said member in a direction parallel to the defined rectilinear path, spring means urging said roller along said linear path into an extreme position, wherein said link is tilted and said member is accordingly held at a normally retracted position below the level of said table surface, and means operable coincident with the descent of the nail punch to advance said roller along said rectilinear path in the oppoe site direction to straighten said link and thus elevate said member to the level of said table surface.

2. In a nailing machine having a descending nail punch, a nail point clinching anvil structure comprising a frame forming a work supporting table Surface containing an opening in alignment with the nail punch, a supporting plate secured to said frame at the lower end of said opening, a roller supported by said plate and constrained to move thereon along a rectilinear path in a direction parallel to said table surface, a member adapted to form a segment of said table surface disposed within said opening above said roller, a link pivotally supporting said member from said roller, spring means urging said roller along said linear path into an extreme position wherein said link is tilted and said member is accordingly held at a normally retracted position below the level of said table surface, and means operable coincident with the descent of the nail punch to advance said roller along said rectilinear path in the opposite direction to straighten said link and thus elevate said member to the level of said table surface.

3. An actuating mechanism for a nail point clincher of the type described comprising a member forming an immovable rearwardly directed surface, an actuating slide constrained to move in a direction perpendicular to said surface, a drawbar constrained to move parallel and adjacent to said rearwardly directed surface, a toggle link pivotally connecting the vicinal ends of said drawbar and said slide, a roller pivotally supported on the end of said toggle link adjacent said rearwardly directed surface to bear against said surface, means operable to move said slide in a direction toward said surface, and yieldable means effective to oppose endwise movement of said drawbar resultingfrom the defined movement of said slide.

4. An actuating mechanism for a nail point clincher of the type described comprising a member forming an immovable outer surface, an actuating slide received within a guideway formed in said member and extending inwardly from said outer surface thereof, a drawbar extending parallel and adjacent to said surface, a toggle link pivotally connecting the projecting end of said slide with the adjacent projecting end of said drawbar, a roller pivotally supported from the projecting end of said drawbar to bear against said outer surface, and means operable to force said slide into said guide way in a manner effective to impart endwise movement to said drawbar.

5. An actuating mechanism for a nail point clincher of the type describedcomprising a member forming an immovable outer vertical surface,

14 an actuating slide received within a guideway' formed in said member and extending inwardly from said outer vertical surface thereof, a drawbar extending parallel and adjacent to said surface, a link pivotally connecting the projecting end of said slide with the adjacent projecting end of said drawbar, a roller pivotally supported from the end of said toggle link adjacent to said outer vertical surface to bear against said surface, means operable to force said slide into said guide way, and spring means engaging said drawbar arranged to oppose endwise movement thereof resulting from operation of said last mentioned means. i

6. An actuating mechanism for a nail point clincher of the type described comprising a member forming first and second immovable vertical outer surfaces arranged at right angles to each other, an actuating slide received within a guideway formed in said member and extending inwardly from said second outer surface thereof, with the projecting end of said slide disposed parallel and adjacent to said first surface, a drawbar disposed parallel and adjacent to said second surface, a link pivotally connecting the projecting end of said slide with said bar at the side of said slide remote from said first surface, a roller pivotally supported from the end of said link adjacent to said second surface to bear against said second surface, another roller pivotally supported from the projecting end of said slide to bear against said first surface; means operable to force said slide into said guideway, and spring means engaging said bar and arranged to oppose movement thereof resulting from the defined operation of said last mentioned means.

7. An actuating mechanism for a nail point clincher of the type referred to comprising a member forming an immovable vertical surface and apair of superposed parallel guideways extending inwardly from said surface, a U-shaped bracket with its parallel shanks slidably received within said guideways, a drawbar extending parallel and adjacent to said surface intermediately of the shanks of said bracket, a vertical shaft supported from said drawbar, a pair of vertically superposed parallel links engaging said shaft and pivoted to respective shanks of said U-shaped bracket at points on the side of said drawbar remote from said surface, and rollers mounted upon said shaft adjacent to said links in contact with said surface.

8. An actuating mechanism for a nail point clincher of the type described comprising a member forming an immovable vertical surface and a pair of superposed parallel guideways extending inwardly from said surface, a U-shaped bracket with its parallel shank slidably received within said guideways, a drawbar extending parallel and adjacentto said surface intermediately of the shanks of said bracket, a vertical shaft supported from said drawbar, a pair of vertically superposed parallel links engaging said shaft and pivoted to respective shank of said U-shaped bracket at points on the side of said drawbar remote from said surface, rollersmounted upon said shaft adjacent to said links in contact with said surface, camming means operable to bear against the connecting bar of said U-shaped bracket to push said bracket with its parallel shanks deeper into said parallel guideways, and means manually adjustable to draw said bracket into said guideways to an extent removing it from the reach of said camming means.

9. a A actuating mechanism for nail point clinch- 15 ers of the type described comprising a member forming first and second immovable vertical surfaces disposed at right angles to each other and a pair of superposed parallel guideways extending inwardly from said second surface adjacent and in a direction parallel to said first surface, a U- shaped bracket disposed adjacent to said first surface with its parallel shanks slidably received within said guideways, a drawbar extending parallel and adjacent to said second surface intermediately of the shanks of said bracket, a vertical shaft supported from said drawbar on the side of said bracket remote from said first surface, a pair of vertically superposed parallel links engaging said shaft and pivoted to respective shanks of said U-shaped bracket at points on the side of said drawbar remote from said second surface, roller pivotally supported from said shanks in contact with said first surface, rollers mounted upon said shaft in contact with said second surface, camming means operable to push said bracket with its parallel shanks deeper into said guideways, and spring means arranged to oppose the movement of said bracket and said drawbar resulting from the defined operation of said camming means.

10. In a nailing machine having a Work supporting anvil and a nail punch arranged to descend upon said anvil and wherein said anvil contains a nail point clincher operated by a pull exerted in a direction transversely of the anvil; an actuating mechanism for said clincher mechanism comprising a member forming an immovable vertical outer surface projecting laterally from the side of the anvil, a drawbar operatively connected to the clincher mechanism and extendingtransversely of the anvil with one end disposed parallel and adjacent to said surface, an actuating slide received in a guideway formed in said member and extending inwardly from said outer surface, a link pivotally connecting the projecting ends of said bar and said slide, a roller pivotally supported at the end of said link adjacent to said vertical surface to bear against said surface, and means operable to force said slide into said guideway coincident with the descent of the nail punch.

11. In a nailing machine having a Work supporting anvil and a nail punch arranged to descend upon said anvil and wherein said anvil contains a nail point clincher operated by a pull exerted in a direction transversely of the anvil, an actuating mechanism for the nail clincher comprising a member forming a first immovable vertical outer surface laterally adjacent a side of the anvil and a second immovable vertical outer surface projecting laterally from the side of the anvil at right angles to said first surface; a drawbar operatively connected to the clincher mechanism and extending transversely of the anvil with one end disposed parallel and adjacent to said second surface; an actuating slide received in a guideway formed in said member and extending inwardly from said second outer surface,

with the projecting end of said slide extending parallel to and adjacent said first outer surface; a link pivotally connecting the projecting end of said slide to the projecting end of said bar; a roller pivotally supported at the end of said link adjacent to said second surface to bear against said second surface; a second roller pivotally supported from the projecting end of said slide to bear against said first surface; means operable to move said slide into said guideway coincident with the descent of the nail punch, thus forcing the projecting end of said bar in a direction away from said first surface; and spring means arranged to urge said bar into the opposite direction.

12., A nailing machine including a work supporting anvil; a nail punch arranged to descend upon said anvil; a nail point clincher mechanism contained. insaid anvil and operable by a pull exerted in a direction transversely of the anvil; an actuating mechanism for said nail clinching mechanism comprising a member forming an immovable vertical outer surface projecting laterally from a side of said anvil, a drawbar operatively connected to the clincher mechanism and extending transversely of the anvil with one end disposedparallel and adjacent to said surface, an actuating slide received in a guideivay formed in said member and extending inwardly from said outer surface thereof, a link pivotally connecting the projecting end of said. slide to the end of said bar at the side of said slide remote from the anvil and a roller pivotally supported at the end of said link adjacentv to said surface to bear against said surface; means operable to cause descent of the nail punch and move said slide into said guideway thus forcing the projecting end of said bar laterally away from the anvil; and spring means arranged to urge said bar into the opposite direction.

13. A nailing machine including a work supporting anvil; a nail punch arranged to descend upon said anvil; a nail point clinching mechanism contained in said anvil and operable by a pull exerted in a direction transversely of the anvil; an actuating mechanism for said nail clinching mechanism comprising a member forming a first immovable vertical outer surface laterally adjacent a side of said anvil and a second immovable vertical outer surface projecting laterally from said anvil side at right angles to said first surface, a drawbar operativeiy connected to the clincher mechanism and extending trans-- versely of the anvil with one end projecting disposed parallel and adjacent to said second surface, an actuating slide received in a guideway formed in said member and extending inwardly from said second surface thereof with the projecting end of said slide disposed parallel and adjacent to said first surface, a link pivotally connecting the projecting ends of said bar and said slide at the side of said slide remote from said first surface, a roller pivotally supported at the end of said'l-ink adjacent to said second surface to bear against said second surface, and a second roller pivotally supported from the projecting end of said slide to bear against said first surface; means operable to cause descent of the nail punch and move said slide into said guideway thus forcing the projecting end of said bar away from said first surface; and spring means arranged to urge said bar into the opposite direction.

14. A nailing machine including an anvil having a work supporting upper surface; a nail punch operable to descend upon said anvil; a nail point clinching mechanism in an opening in the work supporting anvil surface in vertical alignment with said punch and comprising a plate forming asegment of said Work supporting anvil surface; and means operable to elevate said plate temporarily to the level of said Work supporting an vil surface including a drawbar extending transversely of said anvil to protrude laterally beyond one side thereof; an actuating mechanism oper able to move said drawbar in a manner effective orally from the mentioned side of said anvil adjacent and parallel to the projecting endof said drawbar and a guideway extending inwardly from said vertical surface, an actuating slide received said surface; and means operable to force said slide intosaid guideway to .raise said plate to the level of said work supporting anvil surface and cause descent of said punch upon said anvil surface. I i a 15. A nailing machine including an anvil having a work supporting surface; a nail punch operable to descend upon said anvil surface; a nail point clinching mechanism arranged in an opening in said anvil surface in vertical alignment with said punch and comprising a plate forming a segment of said work supporting anvil surface, a support disposed at the lower end of said opening, a roller upon said support operable to roll in a direction transversely of the anvil, a link pivotally supporting said plate from and abovesaid roller, means blocking movement of said plate in a'direction transversely of said anvil, said link being normally in a tilted position wherein it supports said plate at a level below the work supporting anvil surface, and a drawbar engaging the lower end of said link and extending transversely of said anvil to protrudelaterally beyond one side thereof; an actuating mechanism operable to move said drawbar in a manner effective to straighten said link and thus raise said plate to the level of said work supporting anvil surface comprising a member forming an immovable vertical outer surface projecting laterally from the mentioned side of said anvil adjacentland parallel to the projecting end of said drawbar and a guideway extending inwardly from said, outer surface, a slide bracket received within said guideway, a link pivoted to the projecting ends of said drawbar and of said bracket, a roller pivotally supported from said link to bear against said surface, camming means operable to force said bracket into said guideway, spring means opposing the resultant movement of said bracket and said drawbar, and means manually adjust able to urge said bracket into said guideway into a position out of reach of said camming means and with said plate raised to the level of said work supporting anvil surface.

16. A nailing machine including an anvil having a work supporting upper surface; a nail punch operable to descend upon said anvil surface; a nail point clinching mechanism arranged in an opening in said anvil surface in vertical alignment with said punch and comprising a plate forming a segment of said Work supporting anvil surface, a support disposed at the lower end of said opening, a roller upon said support operable to roll in a direction transversely of the anvil, a link pivotally supporting said plate from and above said roller, means blocking movement of said plate in a direction transversely of said anvil, said link being normally in a tilted position wherein it supports said plate at a level below the work supporting anvil surface, and a drawbar engaging the lower end of said link and extending transversely of said anvil to protrude laterally beyond one side thereof; and an actuating mechanism operable to move said drawbar in a manner worksupporting table containing a recess, a hall effective to straighten said link and thus raise said plate to the level of said Work supporting anvil surface comprising a member forming a first immovable vertical surface adjacent said anvil side, a second immovable vertical surface projecting laterally from the mentioned side of and the shanks of said bracket, rollers pivotally supported from the ends of said links adjacent said second surface to bear against said second surface, rollers pivotally supported from the shanks of said bracket to bear against said first surface, camming means operable to force said bracket into said guideways, and spring means opposing the resultant movement of said bracket and said drawbar.

'17. In a nailing machine having a descending nail punch, a frame forming a work supporting table surface containing a recess in alignment With the nail punch, a nail point clinching member slidably disposed within said recess, said member being supported from said frame in a position with its nail point clinching surface normally disposed below the work supporting surface of said frame, means including a reciprocable bar and actuating means therefor operative coincident with the descent of the nail punch to temporarily elevate said nail point clinching surface into substantially flush relation with said work supporting table surface, and adjustable means for varying the relationship of said bar and said actuating means to alter the effective amplitude of the clinching stroke of said nail point clinching member.

18. In a nailing machine, in combination, a

point clinching mechanism mounted on said table including a nail point clinching member slidably disposed within said recess with its nail point clinching surface normally disposed below the work supporting surface of said table, means operative to elevate said nail point clinching surface into substantially flush relation with the Work supporting surface of said table, and means for varying the amplitude of the clinching stroke of said nail point clinching member.

19. In a nailing machine, in combination, a work supporting table containing a transversely disposed guideway and a vertical recess, a nail point clinching mechanism mounted for reciprocative movement within said guideway and including a nail point clinching member slidably disposed within said vertical recess with its nail point clinching surface normally disposed below the work supporting surface of said table, and means operative to reciprocate said clinching mechanism in a manner effective to elevate the nail point clinching mechanism, an actuating slide for said clinching mechanism, means normally acting upon and cooperating with said actuating slide to move it to actuate said clinching mechanism, and means operable in a. manner efiective to withdraw said actuating slide out of reach of said first mentioned means and thus render said nail point clinching mechanism inactive. I

21. In a nailing machine, in combination, a work support, a nail point clinching mechanism mounted for movement relative to said work support, a nail point clinching member mounted for reciprocation relative to said Work support and said clinching mechanism, an actuating slide mounted for reciprocation relative to said work support, means for interconnecting said clinching mechanism and said slide, camming means normally cooperating with said slide for moving the latter to effect actuation of said clinching mechanism and advancement of said nail point clinching member into its nail clinching position, and means operable in a manner efiective to withdraw said actuating slide out of reach of said carnming means and thus render said clinching mechanism inactive while said clinching member is in its advanced nail clinching position.

22. A combination as defined in claim 21, in which the actuating slide is disposed substantially in perpendicular relation to the nail point clinching mechanism and in the operative plane of the camming means.

23. A nailing machine comprising a frame, nail driving mechanism mounted upon said frame, a

work supporting table mounted for adjustment relative to said frame and to said nail driving mechanism, a clinching anvil mounted for reciprocation relative to said Work supporting table, operating mechanism for said nail driving mechanism and said anvil mounted upon said frame,

20 and means operable in a manner effective to move said work supporting table with said clinching anvil beyond the range of said anvil operating mechanism to permit utilization of said nail driving mechanism and said work supporting table for types of work which do not require clinching and subsequently to return said work supporting table with said clinching anvil into the range of said operating mechanism for resumption of nail clinching operations.

24. In a nailing machine, the combination with nail driving mechanism, of a work support for holding work while nails are driven thereinto, a clinching anvil, and mechanism operating in timed relation with said nail driving mechanism for operating said anvil, said operating mechanism including a cam having a portion for maintaining the anvil normally below the work supporting surface of said work support while work is being inserted in said machine, a second porticn for elevating said anvil into substantially flush relation with said work supporting surface while a nail is being driven so as toclinch the point of said nail coincident with its projection through the work, and a third portion for permitting rapid return of the anvil to its normally retracted position.

References Cited in the file of this patent UNITED STATES PATENTS

Images